【单选题】Mercedes estate cars and Fiat runarounds(轻便小汽车) are being used to test up to 22 different monitors designed to detect if a driver is falling asleep at the wheel and trigger a series of devices designe...
A.
the car brake will be activated automatically to prevent an accident
B.
a refined version of smelling salt will be sprayed at the driver
C.
the window will be opened to let in fresh air
D.
a vibrating alarm will sound to wake the driver up